This invention relates to bags that carry corn kernels and are used in popping the corn in a microwave oven, and more particularly to the construction for such a bag.
Bags for use in carrying corn and popping the corn in a microwave oven are known. See for example U.S. Pat. Nos. 4,450,180; 4,548,826; 4,571,337; 4,691,374 and 5,044,777. A frequently used bag is known as the pinch bottom bag and is fabricated from a laminated web of material that is folded and glued. The bag has a front panel, a back panel, a pair of gusseted or folded side panels each of which is connected with the front and the back panel, and a susceptor for receiving the microwave energy and heating the corn kernels.
In this type of bag a flap is formed from the bottom, is folded up therefrom and adhered to the back of the bag so as to close the bottom from side-to-side. This type of end has been referred to as a pinch bottom as opposed to a square bottom. In a recent modification the flap has been eliminated and the bag is sealed closed from side-to-side by an adhesive which completely closes and adheres the front, back and side panels together along interior edges. Glue on the exterior closes the gusset folds at the bottom.
At the top end, the bag is sealed closed and the bonding is along interior edges of the bag. Moreover, the seal at the top is not as strong as that for the bottom. This top construction and sealing permits steam and expanded air to exit the bag as the corn is popped, even though the bottom remains closed.
In a typical situation a bag is folded and formed from the web and the top is open. With the bag top open the bag is then filled with the corn, oil and seasoning. The top of the bag is then closed and the bag is folded so as to form a center section with the ingredients and the ends are folded thereover. The shape is somewhat like a packet with the end flaps folded over the center section. This packet is unfolded and placed in a microwave oven with the flaps opened and the susceptor against the oven floor, where the microwave energy interacts with the susceptor and pops the corn. Steam from the popping exits the top end of the bag.
However, it has been found that some corn kernels move to, and are trapped at the bottom end, particularly in the end gusset folds and do not pop. Sometimes popped corn clumps at the bottom end.
Therefore, it is an object of this invention to provide a bag structure which will minimize the problems of trapping kernels and clumping.
It has also been found that when kernels do not pop, the bag assumes a sloping configuration, rather than the more desirable pillow shape. This sloping can cause the bag to undesirably tilt and the susceptor to tilt out of contact with the oven floor. This in turn may cause the corn to shift and the popping to be uneven. The pillow configuration is more desirable since the tilting may be eliminated or minimized, aesthetically the bag appears more acceptable, there is more surface exposed to carry advertisements, and the bag has a greater internal volume.
Thus, it is another object to provide a bag which will adopt a pillow shape when the kernels are popped.
It has also been found that if the microwave oven is older, not operating efficiently or of a low power or wattage, trapped kernels may not pop.
Thus, it is an even further object of this invention to provide a bag structure which is effective with both newer and older microwave oven units.
In an effort to solve these types of problems, a seal jaw design was developed using a diagonal glue line which formed a triangular gusset adjacent the end. This is seen in U.S. Pat. No. 5,044,777. However, this design requires the use of additional glue in the outside gusset and limits bag expansion by preventing unfolding at the ends. In other words, the bag internal volume reduced. Thus, the bag solved some, but not all of the pre-existing problems.
Other objects of this invention are to avoid the gusset gluing procedure, maximize unfolding and internal volume and maximize the popping of kernels.
Generally, it is desirable to provide the foregoing advantages, minimize the cost for changes while maximizing the functionalbility of the bag.
These and other objects of this invention will become apparent from the following description and appended claims.